[lttng-dev] lttng snapshots and running traces

Thibault, Daniel Daniel.Thibault at drdc-rddc.gc.ca
Thu Sep 26 14:20:42 EDT 2013

Date: Thu, 26 Sep 2013 12:16:29 -0400
From: Julien Desfossez <jdesfossez at efficios.com>

> When the consumer needs to read a subbuffer, it performs a get_subbuf operation. If this operation succeeds, 
> the consumer has exclusive access to this subbuffer and so it can read it safely. If it fails, it means the tracer is 
> currently using it and in the case of snapshots, the consumer will just skip to the next one (up to the end 
> position it defined at the beginning of the snapshot).
> Julien

   Presumably the tracers also use get_subbuf, so what happens if they are refused access because the consumer 
got the sub-buffer first?  Do they wait for the consumer to relinquish the sub-buffer, or do they skip ahead?

Daniel U. Thibault
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